This invention relates generally to the field of closing bags, netting, or casings. This invention relates more specifically to applying a clip to a gathered neck of a bag, a net, or a casing. This invention also relates to attaching a label while applying a clip to a gathered neck of a bag, a net, or a casing. More particularly, the invention relates to the field of packaging edible food products, such as hams, poultry, sausages, and cheeses, in bags, netting, or casings. The invention can be used for closing any materials in a bag, netting, or casing, and is not limited to edible food products.
Many food products are packaged in another material, either for processing or for final sale. Sausages, for example, are made by mixing minced meat and seasonings to produce a pasty product, which is extruded through a product horn into a tubular casing. A clipper creates a void in the extruded tubular casing, gathers the casing into a neck, applies two clips to the neck, and severs the casing between the two clips, to form the back end of a completed sausage and the front end of the sausage still being extruded. Other food products, including hams, turkeys, and whole-muscle products, are produced in a similar fashion.
Some food products are packaged in bags, which must then be closed. Poultry, for example, including in particular whole chickens and chicken parts, are often packaged in clear plastic bags. After the poultry has been inserted into a bag, a clipper gathers the open end of the bag, gathers it into a neck, and applies a clip to close the bag.
Other food products are encased in netting for sale to the final consumer. Larger items such as hams, turkeys, turkey breasts, sausages, and cheeses, are packaged in netting for ease of handling. Typically, one end of tubular netting is closed with a clip, the item is placed within the netting, the netting is gathered tightly around the item, a clip is applied to enclose the item within the netting, and the netting is severed. Often, a loop is formed in one end of the netting to create a handle on the package, to ease handling of the items, which may be heavy, and to allow consumers to lift the items without actually touching the items. Sometimes a label is attached to one of the clips to provide identifying information.
In some situations, items are packaged in netting in order to enhance the appearance of the items after processing. For example, sausages, hams, and cheeses are often encased in tubular netting, as described above, prior to processing. During processing, such as in a smokehouse, the item expands within the netting and pushes through the mesh of the netting. After processing, the netting is removed and discarded. The item retains a dimpled appearance that is considered pleasing to consumers.
In most situations described above, as well as in other situations, the bag, casing, or netting must be closed securely. If a consumer picked up a large item such as a turkey and the netting slipped, an injury could result, either from the turkey falling out one end of the netting or by the handle pulling tightly about the consumer's fingers. During smoking of hams or sausages, if the netting did not hold tight about the item, the item would not expand through the mesh of the net and would not obtain the dimpled appearance that is considered desirable. If a bag of chicken was not sealed tightly, liquids within the bag could leak out, creating not only an appearance unsightly to consumers but also a health hazard.
Clips are generally used to seal packages in the situations described above, as well as in many other situations. (The common office staple, for example, that holds pieces of paper together, is a clip.) An exemplary clip as is known in the prior art is described in U.S. Pat. No. 6,401,306, Sealing Clips For Bags And Tubes And Matrix For Sealing The Latter.
A conventional prior-art clip 10 is shown in FIG. 1. Clip 10 has a top section 12 from which project two identical legs 14, defining a space 16 between the legs 14. Legs 14 are often pointed, to ease entry into the grooves of a die or to punch through material. A series of clips are usually assembled into a cartridge, held together by glue or tape, which is loaded into a clipper. The cartridge of clips is often carried on a rail to the operating point of the clipper.
Clips are closed by a combination of a punch and a die. The clipper orients the first clip 10 from a cartridge over a neck of a gathered bag, casing, or netting, so that the neck is within the space 16. A punch presses on the top section 12 of the clip, forcing the legs 14 into grooves on a die. The grooves force the legs 14 inward toward each other as the punch descends, until the legs have closed to form an aperture surrounding the neck of gathered bag, casing, or netting.
The punch-and-die system of the prior art requires quite a bit of power to operate, as a great deal of pressure is required to close a clip by punching the top of it. Additionally, precise control of the amount of punching power is required. Enough punch power must be applied to seal the clip, especially for food products, which must be thoroughly sealed. Too much punch, however, will destroy the bag, casing, or netting, contrary to the intended purpose of the system. Achieving the proper power for the punch is a problem for clipper manufacturers.
Additionally, precise alignment is required, in order for the legs 14 of the clip to enter into the grooves of the die. If the alignment is off by even a small amount, the legs 14 will not enter the grooves and will not be bent inward in the proper manner to seal the package. The need for precise alignment produces high maintenance and operating costs.
Moreover, a punch-and-die system is relatively slow.
Accordingly, needs exist for a clip closure system that uses less power, requires less precise alignment, and operates faster than the system of the prior art. The present invention meets these needs.